You need a program that converts formats into DVD vob files and optionally writes the disc for you. I use Xilisoft DVD creator, it converts pretty much anything you want (avi/slv/mpg) to DVD and does it all in one. Xilisoft make a great selection of tools.

thanks mercury rapids, I think that was the info I needed. I download vids using realplayer but I can only burn those shorter than an hour onto cd. many people have dvd's that wont play cd, so if I change the file size, can I burn onto dvd using realplayer or do I use nero for this? My 12 year old son said something about changing the file size the other day but im clueless

ConvertXtoDVD converts the flv files to the files you get on a regular video DVD (.vob etc.). Then in Nero, or whatever, you select the option to burn a DVD-Video and just add the files that ConvertXtoDVD has created into the Video folder on the DVD to be burnt.

I was using Wondershare software which does the same job but had too many glitches so found AVS and it is great. It will even convert the VOB file to another format if you so desire...but you have to buy the complete package.